Microbial Fuel Cells Provide Enough Power for Small DevicesOne option which is being investigated in a pilot project by Cambridge, Massachusetts company Lebônê Solutions is using microbial fuel cells to provide electricity to villagers in Tanzania. While the power produced by microbial fuel cells isn’t great, it does provide enough electricity for the small DC powered devices that the villagers want to run, Lebônê co-founder Hugo Van Vuuren told Technology Review. Compared to other renewable energy options such as solar panels or small-scale wind turbines they are also less expensive to produce and easier to set up.A What Type of Fuel Cell?Lebônê gives us a very basic rundown on how microbial fuel cells work:

These inexpensive fuel cells run on animal and plant waste and naturally occurring soil microbes, and are framed around a flexible substrate (wood, steel, etc) that can vary by geographic availability. This is truly electricity right out of the ground. These fuel cells are used to charge a battery or cheap supercapacitor, which in turn will be used to power a high-efficiency efficient LED or PLED lamp.

And Technology Review gives us a bit more detail:

To make the fuel cell, the team put graphite cloth--the anode--in the bottom of a bucket along with chicken wire--the cathode--and microbe-laden waste, either mud, cow manure, or residue from coffee crops. A layer of sand acts as an ion barrier while salt water helps the protons travel more easily. The team adds a power management board (the only device that the villagers will most likely have to import, says [Lebônê co-founder Aviva] Presser) to regulate the power and send it to a battery. Such a fuel cell can run a cheap, efficient light-emitting diode (LED) for four to five hours per evening. "We're hoping the entire system will be around $10 when we're ready," says Presser.

Namibia Next Up For Fuel Cell TrialAfter Tanzania, Lebônê’s second trial, funded by a $200,000 grant from the World Bank, will be an 18-month pilot project in Namibia where the the firm will couple their fuel cell design with the the next generation of LEDs.